Reduced sidestream smoke smoking article wrappers, methods of making such wrappers and smoking articles made from such wrappers

ABSTRACT

A cigarette or cigar wrapper is disclosed wherein the paper filler consists of two homogeneously intermixed minerals, viz huntite and hydromagnesite, alone, or admixed with calcium carbonate or magnesium hydroxide or calcium carbonate and magnesium hydroxide and carbon.

SUMMARY OF THE INVENTION

This invention relates to smoking articles, such as cigarettes, cigarsand the like, and the wrapper for the tobacco column thereof, thatprovide acceptable burn rates, produce light-colored, well-formed ashwhich clings tightly without premature flaking, have significantlyreduced sidestream smoke generation compared to conventional cigarettesand deliver both mainstream and sidestream smoke with acceptable tasteand aroma. These desirable properties are achieved when certain definedlevels of ULTRACARB (a mineral additive and a paper filler consisting oftwo homogeneously intermixed minerals, viz huntite and hydromagnesite).

The ULTRACARB may be used as the only filler, or in combination withcalcium carbonate co-filler, in combination with magnesium hydroxide andcalcium carbonate co-fillers, or in combination with magnesiumhydroxide, calcium carbonate and carbon co-fillers, to produce a basecigarette paper or cigar wrapper. The paper may be subjected totreatment with burning chemicals, such as alkali metal salts ofcarboxylic acids. ULTRACARB wrappers can be employed as a normalcigarette paper or as an inner liner. Organic or inorganic acidtreatment of such papers can be utilized to improve the subjective tasteproperties of the resulting cigarettes. Such papers can also be used incombination with filter dilution and perforation of the base paper tooptimize taste and mainstream smoke yields.

BACKGROUND OF THE INVENTION

The reduced sidestream smoke cigarette paper patents which describemagnesium oxide/magnesium hydroxide as paper fillers, and which defineburning chemical types and levels, are U.S. Pat. Nos. 4,231,377;4,450,847; 4,881,557; and 4,915,118. These patents claim alkali metalacetates, citrates, nitrates, carbonates ad tartrates as burningchemical types at levels in the sheet ranging from 0.5% to 8.0%.

Other patents which relate to reduced sidestream smoke cigarette papersare U.S. Pat. Nos. 4,461,311 and 4,805,644. These patents disclosesodium and potassium salts of succinic, carbonic, formic, acetic,propionic, malic, lactic, glycolic, citric, tartaric, fumaric, oxalic,malonic, nitric, and phosphoric acids at levels in the sheet up to 25%weight. U.S. Pat. No. 4,805,644, dealing with reduced sidestream smokecigarette paper, discloses that various paper fillers with superficialsurface areas of at least 20M² /g result in a wrapper that providesreduced sidestream smoke when incorporated in paper at 5% to 50% byweight.

U.S. Pat. No. 3,744,496 discloses a carbon-filled paper wrapper forcigarettes and/or cigars, preferable used as an inner liner with regularcigarette paper or cigar wrapper as an outer wrap.

DETAILED DESCRIPTION OF THE INVENTION

It has been experimentally determined that cigarette paper withULTRACARB as a filler in the furnish of the paper, by itself, or incombination with a calcium carbonate co-filler, or in combination withcalcium carbonate and magnesium hydroxide co-fillers, or in combinationwith calcium carbonate, magnesium hydroxide and activated carbonco-fillers, provides an enhancement in sidestream smoke reductioncompared to that of a conventional calcium carbonate-filled cigarettepaper while maintaining acceptable ash quality, static burn rate,mainstream and sidestream taste and aroma. The truly novel feature ofthis invention is the reduced sidestream smoke obtained with this uniquefiller. ULTRACARB is a novel mineral based on a unique deposit of twohomogeneously intermixed minerals, viz huntite Mg₃ Ca(CO₃)₄ andhydromagnesite Mg₄ (CO₃)₃ (OH)₂.3H₂ O. On exposure to heat, the mineralsin ULTRACARB decompose presumably as follows:

    Mg.sub.3 Ca(CO.sub.3).sub.4 3 MgO+CaO+4CO.sub.2

    Mg.sub.4 (CO.sub.3).sub.3 (OH).sub.2.3H.sub.2 O 4MgO+3CO.sub.2 +4H.sub.2 O

These reactions are strongly endothermic with a heat change ΔH=1000 J/gand generate non-combustible, non-toxic, non-corrosive gases. ULTRACARBmineral filler is marketed in the U.S. by Anzon Incorporated, 2545Aramingo Avenue, Philadelphia, Pa. 19125, and is supplied worldwide byMicrofine Minerals Limited, Raynesway, Derby, Great Britain.

    ______________________________________                                        PARAMETERS OF THE INVENTION                                                                   % of the Basis Weight of Paper                                ______________________________________                                        Basis Weight of Paper:                                                                        20 to 100 g/M.sup.2 (preferred 35 to                                          65 g/M.sub.2)                                                 ULTRACARB Content:                                                                            5% to 50% (preferred 10% to 35%)                              Calcium Carbonate Content:                                                                    0% to 40% (preferred 10% to 30%)                              Activated Carbon Content:                                                                     0% to 25% (preferred 0% to 15%)                               Magnesium Hydroxide                                                                           0% to 25% (preferred 5% to 15%)                               Content:                                                                      Acid Addition:  0% to 10% (preferred 0% to 3%)                                Porosity Base Sheet:                                                                          3 to 50 (cm/min) CORESTA                                                      preferred 5 to 15 (cm/min)                                                    CORESTA                                                       ULTRACARB Types Untreated and surface modified                                                (stearate, olefinic treated),                                                 ULTRACARB U5, ULTRACARB                                                       C5, ULTRACARB C5-25                                                           ULTRACARB P5-20 and L5                                        Burning Chemical:                                                                             Alkali metal salts of carboxylic                                              acids selected from a group consist-                                          ing of citric, malic, lactic, glycolic,                                       tartaric, fumaric, maleic, malonic,                                           glutaric, adipic, acetic and succinic,                                        in combination with or without                                                sucrose and organic carboxylic                                                acids named above.                                            Burning Chemical Addition                                                                     0.5% to 6%                                                    Rate:                                                                         Smoking Articles:                                                                             Cigarettes, Cigars, and the like                              ______________________________________                                        TYPICAL PROPERTIES OF ULTRACARB                                               TYPES U5, L5, C5, C5-25 AND P5-20                                             ______________________________________                                        U5                                                                            Typical Chemical                                                              Analysis:                                                                     Magnesium      as MgO          38%                                            Calcium        as CaO          8%                                             Silicon        as SiO.sub.2    0.3%                                           Aluminum       as Al.sub.2 O.sub.3                                                                           0.06%                                          Potassium      as K.sub.2 O    0.01%                                          Iron           as Fe.sub.2 O.sub.3                                                                           0.02%                                          Sulphur        as SO.sub.3     0.02%                                          Titanium       as TiO.sub.2    0.02%                                          Loss on Ignition                                                                             (44% CO.sub.2 + 9% H.sub.2 O)                                                                 53%                                            Acid insoluble matter          0.2%                                           Water soluble salts            0.1%                                           Typical Physical                                                              Properties:                                                                   Specific Gravity               2.5                                            Oil Absorption g/100 g         40                                             Refractive index                                                                             mean            1.56                                           Specific Surface area                                                                        m.sup.2 /g      15                                             (nitrogen absorption)                                                         Mean spherical diameter                                                                      Micron          0.16                                           (nitrogen absorption)                                                         Color: Tristimulus Values                                                                    X               95                                             (MgO = 100)    Y               95                                                            Z               94                                             Bulk Density - loose                                                                         Kg/liter        0.23                                           pH             (10% aqueous    9                                                             suspension)                                                    Particle shape                 platey                                         Typical Particle Size                                                         Distribution                                                                  Percentage finer as                                                                           10 micron      99.9                                           measured by Micromeritics                                                                      5 micron      95                                             "Sedigraph"      2 micron      80                                                              1 micron      70                                                            0.5 micron      65                                                            0.2 micron      55                                             L5                                                                            Typical Chemical                                                              Analysis                                                                      Magnesium      as MgO          38%                                            Calcium        as CaO          8                                              Silicon        as SiO.sub.2    0.3%                                           Aluminum       as Al.sub.2 O.sub.3                                                                           0.06%                                          Potassium      as K.sub.2 O    0.01%                                          Iron           as Fe.sub.2 O.sub.3                                                                           0.02%                                          Sulphur        as SO.sub.3     0.02%                                          Titanium       as TiO.sub.2    0.02%                                          Loss on ignition                                                                             (44% CO + 9% H.sub.2 O)                                                                       53                                             Acid insoluble matter          0.2%                                           Water soluble salts            0.1%                                           Typical Physical                                                              Properties                                                                    Specific Gravity               2.5                                            Oil Absorption g/100 g         40                                             Refractive Index                                                                             mean            1.56                                           Specific Surface Area                                                                        m.sup.2 /g      15                                             (nitrogen absorption)                                                         Mean Spherical Diameter                                                                      Micron          0.16                                           (nitrogen absorption)                                                         Color: Tristimulus Values                                                                    X               95                                                            Y               95                                                            Z               94                                             Bulk Density - loose                                                                         kg/liter        0.23                                           pH             (10% aqueous    9                                                             suspension)                                                    Particle shape                 platey                                         Thermogravimetric                                                             Analysis                                                                                                     Cumulative                                     Approx. Decomposition                                                                        Weight          Weight                                         Temperature (degree C.)                                                                      Loss %          Loss %                                         100 (moisture) 0.5             0.5                                            300            5.5             6                                              400            14              20                                             500            11              31                                             600            16              47                                             700            6               53                                             Thermal decomposition onset temperature 230° C.                        P5                                                                            ULTRACARB P5 is a carboxylate-coated, partially hydrated                      magnesium calcium carbonate.                                                  Technical data for the uncoated product ULTRACARB U5 also                     applies for the surface-treated P5 version. The only significant              differences are lower oil absorption (30 g oil per 100 g), slightly           higher loss on ignition and a slightly lower pH.                              ULTRACARB P5 offers the same benefits over the standard, un-                  coated U5 grade that are offered by the stearate-coated C5 range.             ULTRACARB P5 is preferred over C5 grades where higher                         loading levels are desired.                                                   The standard product, having a 2% surface coating is                          ULTRACARB P5-20. Coating levels can be varied, e.g.,                          ULTRACARB P5-10 has a 1.0% coating.                                           C5                                                                            ULTRACARB C5 is a stearate-coated, hydrated magnesium                         calcium carbonate.                                                            Technical data for the uncoated product ULTRACARB U5 also                     applies for the surface-treated C5 version. The only significant              differences are lower oil absorption (30 g oil per 100 g), slightly           higher loss on ignition and a slightly lower pH.                              The standard product having a 1% stearate coating is                          ULTRACARB C5-10. Stearate coating levels can be varied, as                    desired; e.g., ULTRACARB C5-25 has a 2.5% coating.                            ______________________________________                                    

                                      TABLE 1                                     __________________________________________________________________________            Basis                                       Static                    Cigarette                                                                             Weight                                                                            CaCO.sub.3                                                                        Mg(OH).sub.2                                                                       ULTRACARB                                                                             Carbon                                                                             Porosity          Burn                                                                                SSDR.sup.1          Paper   (g/M.sup.2)                                                                       (%).sup.3                                                                         (%).sup.2                                                                          (%)     (%)  Coresta                                                                            Fillers      (mg/min)                                                                            (mg/min)            __________________________________________________________________________    Control -                                                                             22.5                                                                              30.0                                                                              0.0  0.0     0.0  25.0 CaCO.sub.3   56.7  2.13                Ecusta                                                                        12556                                                                         Heavyweight +                                                                         45.0                                                                              20.0                                                                              0.0  0.0     0.0  9.0  CaCO.sub.3   50.7  1.46                1% Citrate                                                                    RSS.sup.3                                                                             45.0                                                                              15.0                                                                              0.0  25.0    0.0  6.0  ULTRACARB U5 51.6  0.95                                                       CaCO.sub.3                             RSS.sup.3                                                                             45.0                                                                              15.0                                                                              0.0  25.0    0.0  6.0  ULTRACARB C5-10,                                                                           49.5  0.90                                                       CaCO.sub.3                             RSS.sup.3                                                                             45.0                                                                              15.0                                                                              10.0 15.0    0.0  7.0  ULTRACARB U5 51.3  0.85                                                       CaCO.sub.3, Mg(OH).sub.2               RSS.sup.2                                                                             45.0                                                                              10.0                                                                              10.0 20.0    0.0  6.0  ULTRACARB U5 49.7  0.87                                                       Mg(OH).sub.2, CaCO.sub.3               RSS.sup.2                                                                             45.0                                                                              5.0 10.0 25.0    0.0  6.0  ULTRACARB U5 45.9  0.84                                                       CaCO.sub.3, Mg(OH).sub.2               RSS.sup.2                                                                             45.0                                                                              0.0 10.0 30.0    0.0  7.0  ULTRACARB U5 47.6  0.98                                                       Mg(OH).sub.2                           RSS.sup.2                                                                             45.0                                                                              0.0 0.0  40.0    0.0  6.0  ULTRACARB U5 52.3  0.99                RSS.sup.2                                                                             45.0                                                                              0.0 10.0 30.0    0.0  6.0  ULTRACARB U5 35.2  0.63                                                       Mg(OH).sub.2                           RSS.sup.2                                                                             45.0                                                                              0.0 0.0  40.0    0.0  7.0  ULTRACARB U5 49.5  0.93                RSS.sup.4                                                                             45.0                                                                              15.0                                                                              25.0 0.0     0.0  10.0 Mg(OH).sub.2, CaCO.sub.3                                                                   75.3  0.93                RSS.sup.4                                                                             45.0                                                                              25.0                                                                              15.0 0.0     0.0  10.0 Mg(OH).sub.2, CaCO.sub.3                                                                   74.9  1.09                RSS.sup.3                                                                             45.0                                                                              20.0                                                                              10.0 0.0     10.0 5.0  Mg(OH).sub.2, Carbon                                                                       49.5  0.77                                                       CaCO.sub.3                             RSS.sup.3                                                                             45.0                                                                              5.0 10.0 15.0    10.0 4.0  Mg(OH).sub.2, ULTRACARB                                                                    44.9  0.65                                                       U5, CaCO.sub.3 carbon                  RSS.sup.3                                                                             45.0                                                                              0.0 10.0 20.0    10.0 4.0  Mg(OH).sub.2, ULTRACARB                                                                    44.3  0.65                                                       U5, carbon                             __________________________________________________________________________     .sup.1 SSDR = Sidestream Delivery Rate (mg/min)                               .sup.2 Burning Chemical Content  8% potassium citrate                         .sup.3 Burning Chemical Content  6.5% potassium + 3% citric acid + 6%         sucrose                                                                       .sup.4 Burning Chemical Content  4.8% potassium acetate                       COMMENTS ON TABLE 1                                                           It can be concluded from Table 1 that ULTRACARB fillers are effective in      significantly reducing the sidestream smoke delivery rate either as a         paper filler by itself, in combination with calcium carbonate and             magnesium hydroxide cofillers, or in combination with calcium carbonate,      magnesium hydroxide and carbon cofillers. Burn rate control depends upon      burning chemical type and level, sheet porosity, filler type and level an     sheet density.                                                           

                  TABLE 2                                                         ______________________________________                                        Ash Properties                                                                Test Cigarettes - Commercial "LIGHTS 100's" with standard                     paper removed and replaced with the experimental reduced                      sidestream smoke cigarette paper.                                             Cigarette Paper                                                                            Static Ash   Puffed Ash                                          ______________________________________                                        Control.sup.1                                                                              Tight shrinkage                                                                            Tight shrinkage                                                  Light Grey   Light Grey                                                       No flake fall off                                                                          No flake fall off                                                Solid sheath Small adhering flakes                               45 g/M.sup.2.spsp.2                                                                        Tight shrinkage                                                                            Tight shrinkage                                     ULTRACARB - 40%                                                                            Light Grey   Light Grey                                                       Few loose flakes                                                                           No flake fall off                                                Small flakes Small flakes                                        45 g/M.sup.2.spsp.3                                                                        Tight shrinkage                                                                            Tight shrinkage                                     ULTRACARB - 25%                                                                            Light Grey   Light Grey                                          Calcium Carbonate -                                                                        No flake fall off                                                                          No flake fall off                                   15%          Solid sheath Solid sheath                                        ______________________________________                                         .sup.1 Ecusta 12556 cigarette paper: 30% calcium carbonate; 25 CORESTA        porosity; 25 g/m.sup.2 ; 0.55 citrate burning chemicals.                      .sup.2 40% ULTRACARB U5 filler: 6 CORESTA porosity; 45 g/M.sup.2 ; 6.5%       potassium citrate + 3% citric acid + 6% sucrose burning chemical.             .sup.3 25% ULTRACARB U5 filler: 15% calcium carbonate filler; 6 CORESTA       porosity; 45 g/M.sup.2 ; 8% potassium citrate burning chemical.               Comments on Table 2                                                           The data in Table 2 indicate that both ULTRACARB by itself and the            ULTRACARB/calcium carbonate combination result in ash properties very         similar to that obtained with regular cigarette paper (control).         

                  TABLE 3                                                         ______________________________________                                        Particle Size and Surface Area Characteristics of                             ULTRACARB Filler                                                                                            Particle                                                                              Specific.sup.(2)                                                      Size.sup.(1)                                                                          Surface                                                   Chemical    Sedigraph                                                                             Area                                    Filler   Vendor   Composition (μm) (M.sup.2 /g)                            ______________________________________                                        ULTRA-   Anzon    Huntite     0.16    15                                      CARB U5           Hydromagnesite                                              ULTRA-   Anzon    Huntite     0.16    15                                      CARB C5           Hydromagnesite                                              ______________________________________                                         .sup.(1) Particle Size measured by Micromeritics Sedigraph instrument.        .sup.(2) Surface Area measured by B.E.T. Nitrogen Adsorption method.          Comments on Table 3                                                           It should be noted that specific surface area for ULTRACARB is only 15        M.sup.2 /g which is less than the minimum 20 M.sup.2 /g filler surface        area claimed by Hampl, et al, (U.S. Pat. No. 4,805,644), as being require     for effective sidestream smoke reduction. The outstanding sidestream smok     reduction demonstrated by cigarettes wrapped in papers containing             ULTRACARB fillers contradicts the Hampl, et al, claim that sidestream         smoke reduction increases with increasing filler surface area.           

We claim:
 1. A wrapper for smoking articles comprising a cellulosicsheet and an ultracarb, a homogeneous mixture of huntite andhydromagnesite, filler concentration in the sheet in the range of 5% to50% of the basis weight of the cellulosic sheet.
 2. The wrapper, asdefined in claim 1, further including calcium carbonate as a co-fillerat levels up to 40% of the basis weight of the sheet.
 3. The wrapper, asdefined in claim 1, further including magnesium hydroxide as a co-fillerat levels up to 25% of the basis weight of the sheet.
 4. The wrapper, asdefined in claim 1, further including calcium carbonate at levels from10% to 30% of the basis weight of the sheet and activated carbon atlevels up to 25% of the basis weight of the sheet as co-fillers.
 5. Thewrapper, as defined in claim 1, further including activated carbon as aco-filler at levels up to 25% of the basis weight of the sheet.
 6. Asmoking article comprising a tobacco charge and a wrapper for thetobacco charge, said wrapper comprising a cellulosic sheet and anultracarb, a homogeneous mixture of huntite and hydromagnesite, fillerconcentration int he sheet in the range of 5% to 50% of the basis weightof the cellulosic sheet. sheet in the range of 5% to 50% of the basisweight of the cellulosic sheet.
 7. A smoking article, as defined inclaim 6, further including calcium carbonate as a co-filler at levels upto 40% of the basis weight of the sheet.
 8. A smoking article, asdefined in claim 6, further including magnesium hydroxide as a co-fillerat levels up to 25% of the basis weight of the sheet.
 9. A smokingarticle, as defined in claim 6, further including calcium carbonate atlevels from 10% to 30% of the basis weight of the sheet and activatedcarbon at levels up to 25% of the basis weight of the sheet asco-fillers.
 10. The wrapper, as defined in claim 6, further includingactivated carbon as a co-filler at levels up to 25% of the basis weightof the sheet.
 11. A method of reducing sidestream smoke of smokingarticles wrapped in a cellulosic sheet comprising forming the sheet withan ultracarb, a homogeneous mixture of huntite and hydromagnesite,filler at levels int he range of 5% to 50% of the basis weight of thecellulosic sheet.
 12. The method, as defined in claim 11, furtherincluding adding to the sheet calcium carbonate as a co-filler at levelsup to 40% of the basis weight of the sheet.
 13. The method, as definedin claim 11, further including adding to the sheet magnesium hydroxideat levels up to 25% of the basis weight of the sheet.
 14. The method, asdefined in claim 11, further including adding calcium carbonate atlevels from 10% to 30% of the basis weight of the sheet and activatedcarbon at levels up to 25% of the basis weight o the sheet asco-fillers.
 15. The method, as defined in claim 11, further includingadding activated carbon as a co-filler at levels up to 25% of the basisweight of the sheet.